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Old 05-03-2021, 02:27 PM   #1
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Convert 2-50amp legs to 1 -100amp legs

After working thru all the mismatches of wire/breaker/load issues(see previous posts about that) then working thru all the balancing leg issues(see previous post about that) I'm now thinking. What would it take to convert these 2-50amp legs to 1 - 100 amp leg, besides a licensed knowledgeable ABYC certified electrician?

I have No 240v loads.

Research on this topic says I crazy and it's not going to happen, Probably correct.

The Brockerts
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Old 05-03-2021, 03:38 PM   #2
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Are the two 50A circuits 120V or 120/240V?
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Old 05-03-2021, 03:55 PM   #3
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Are the two 50A circuits 120V or 120/240V?
The line coming in is connected to a 50A 125/250v connection, 3 prong plug with gnd on the outer edge. Each leg measures 120v from prong to gnd.
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Old 05-03-2021, 05:41 PM   #4
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How many docks have 100 amp 120 volt outlets? That would be a concern. If there are not any docks that have them then it would futile to even try.
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Old 05-03-2021, 06:00 PM   #5
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I dont understand what service you have available, whats wrong with the current set up or what the objective is.
I suspect the lack of responses may indicate others are similarly confused.
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Old 05-03-2021, 07:10 PM   #6
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Quote:
Originally Posted by The Brockerts View Post
After working thru all the mismatches of wire/breaker/load issues(see previous posts about that) then working thru all the balancing leg issues(see previous post about that) I'm now thinking. What would it take to convert these 2-50amp legs to 1 - 100 amp leg, besides a licensed knowledgeable ABYC certified electrician?

I have No 240v loads.

Research on this topic says I crazy and it's not going to happen, Probably correct.

The Brockerts
What is the need? 50a 125/250v is 100 amps of 125v. Mind you, it is split between two different buses. Now if you have one appliance that needs 60 amps of 125v this is a problem. It’s just that I am unfamiliar with any system that needs this unless we are talking about a 90’ boat. Even then most systems go to 240v at 30a instead of 125v at 60a.
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Old 05-03-2021, 07:21 PM   #7
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Going to individual legs bigger than 50A just isn't practical, as you won't find suitable hookups at most marinas.



What loads are you having trouble balancing?
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Old 05-03-2021, 07:39 PM   #8
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Need to close this thread out. I've been digging around and even if you could convert, there are very few Marinas that offer the service.

The problem is I've loaded up one 50amp line with 2 A/C units. That's 30amps when running. The remaining 20amps are worthless because of startup loads. I stick a microwave on that line and then one A/C unit kicks in and pop the breaker goes, or the hotwater kicks in, pop the breaker goes.

Now multiply by 2(I've got 4 A/C unit's) and I can't cook a meal without shutting down two A/C units.

You want to run the range and microwave, shut down half of the A/C units.

I how have a list of how to setup the electric panel based on what we are cooking each evening.

With a 100amp line I could use 20-30amps that I can't now.

I live in Corpus Christi, Texas and getting ready for summer. Low's temp at night will be in the 80's and daytime highs 95+. Humidly steady in the 80+ range. You really don't want to live here 5 months of the year, and I won't after this summer, as I'll be heading north.

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Old 05-03-2021, 07:46 PM   #9
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How big are your A/C units? My second 50A leg has all 3 of my A/Cs (2x 10k and a 16k) on it, plus the microwave. Using all 3 A/Cs and the microwave is pushing it, but can be done. 2 units plus the microwave is fine. The rest of my loads (stove, chargers, water heater, etc.) are on the other 50A leg.



For your breaker tripping issue, make sure the 50A main breakers are in good shape and replace them if you have any doubt. Sometimes old breakers start to trip a bit early. Also, look into soft start units for your A/Cs to reduce the startup spike a bit.



Beyond that, it's just a matter of thinking about which loads do you need to use at the same time, and which aren't used much, or are typically used in an "A or B" scenario. Use that to determine what goes to each 50A leg.
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Old 05-03-2021, 08:36 PM   #10
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As suggested reducing the startup loads may help. Yes a Soft start or a larger starting capacitor, often referred to as HARD START CAPS, can often get the compressor motor over the hump faster than the standard capacitor. Then the C.B. may hold long enough to avoid nuisance trips.
Check the connections at the breaker. Clean them including the wire lugs and recrimp them to break any oxidation. Any connection oxidation will heat the breaker making a trip more likely. Double check the connections at the machine also as any excessive Voltage loss will cause the motor to draw more current for longer which will push a hard working C.B. to trip more readily.


A link:

https://www.google.com/search?q=best...hrome&ie=UTF-8

These are quite common in the RV side of things.
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Old 05-03-2021, 10:26 PM   #11
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Or just move one A/C to the other 50 amp leg. Not a very difficult job.
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Old 05-04-2021, 12:41 AM   #12
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My experience, but not necessarily applies to your situation, two 16,000 btu A/C run at 26 amps and only momentarily jump to 30 on start up. I run three heat pumps on one circuit, this draws 39 amps and jumps to 42 on start up. Since a good 50 amp circuit breaker should hold up to 54 amps you shouldn’t have a problem even on start up. This would give you an additional 40 amps to play with on the second leg.
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